How the slimy hagfish ties itself up in knots— and survives shark attacks

NEW ORLEANS, LOUISIANA—When people say they get all tied up in knots, they don’t mean it literally. Such is not the case for the hagfish, a jawless, eellike creature that ties itself into pretzellike twists to tear apart its dinner. Hagfish are best known for their slime, which gums up the gills of any predator that tries to eat them, causing the attacker to spit them out unharmed. But hagfish have other unusual attributes: They can squeeze through devilishly tight spaces and survive shark bites unscathed, researchers reported here this week at the annual meeting of the Society of Integrative and Comparative Biology.

Hagfish aren’t a typical fish—they have cartilage instead of bones and a primitive skeletal rod (called a notochord) instead of a backbone. For years, Douglas Fudge studied their fibrous slime, which they make in enormous quantities when stressed. Then in 2011, the marine biologist at Chapman University in Orange, California, saw a video of a shark chomping down on a hagfish, which escaped without a scratch. Had its slimy coating and tough skin saved it?